An optical pick-up is used to read or/and record information in a disc, such as a digital video disc (DVD) or a compact disc (CD) in an optical disc driver. As shown in FIG. 1A, the optical disc driver generally includes a turntable 18 for supporting and turning a disc 20, an optical pick-up 14 and the guiding shafts 11 and 12. Besides, there is a motor (not shown) for driving the optical pick-up 14 to move along the guiding shafts 11, 12. In other words, the motor drives the optical pick-up 14 to move along the radius direction of the disc 20 such that the optical pick-up 14 can read the entire information in the disc 20. The guiding shafts 11 and 12 respectively have two different ends and at least one end of each guiding shaft is connected to the optical disc driver by a screw, such as 151, 152, and 153 shown in FIG. 1B.
Conventionally, the information is stored in units that are either 0 or 1 so that there are different pits on the disc 20. The information is read by measuring the intensity of a laser beam reflected on the pits of a reflective layer on the disc 20 and by subsequent decoding.
When the optical disc driver reads or records information on the disc 20, the laser beam projecting from the optical pick-up 14 impinges perpendicularly on the disc 20, as shown in FIG. 2. Accordingly, the optical pick-up 14 receives the laser beam reflected from the pits. However, there is an undesired angle between the direction of the laser beam and the normal direction of the disc 20 as inaccurate assembly of component the optical disc driver occurs. The angle is defined as the tilt angle 28. The tilt angle 28 causes the inability of the optical pick-up 14 to receive the laser beam reflected from the disc 20 thereby leading to the reading error, or transmission breaking off, etc. When the data density on the disc 20 increases, this problem becomes more severe.